Bearing assemblies, apparatuses, and motor assemblies using the same

ABSTRACT

Bearing assemblies, apparatuses, and motor assemblies using the same are disclosed. In an embodiment, a bearing assembly may include a plurality of superhard bearing elements distributed circumferentially about an axis. Each of the superhard bearing elements may include a bearing surface. At least one of the plurality of superhard bearing elements may include at least one texture feature that may be formed in a lateral surface thereof. The bearing assembly may also include a support ring that carries the superhard bearing elements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/432,224 filed on 28 Mar. 2012, which is a continuation-in-part ofU.S. patent application Ser. No. 13/234,252 filed on 16 Sep. 2011, nowU.S. Pat. No. 8,950,519 issued on 10 Feb. 2015, which is acontinuation-in-part of U.S. patent application Ser. No. 13/116,566filed on 26 May 2011, now U.S. Pat. No. 8,863,864 issued on 21 Oct.2014. Each of the foregoing applications is incorporated herein, in itsentirety, by this reference.

BACKGROUND

Subterranean drilling systems that employ downhole drilling motors arecommonly used for drilling boreholes in the earth for oil and gasexploration and production. Such a subterranean drilling systemtypically includes a downhole drilling motor that is operably connectedto an output shaft. A pair of thrust-bearing apparatuses also can beoperably coupled to the downhole drilling motor. A rotary drill bitconfigured to engage a subterranean formation and drill a borehole canbe connected to the output shaft. As the borehole is drilled with therotary drill bit, pipe sections may be connected to the subterraneandrilling system to form a drill string capable of progressively drillingthe borehole to a greater size or depth within the earth.

Each thrust-bearing apparatus includes a stator that does not rotaterelative to the motor housing and a rotor that is attached to the outputshaft and rotates with the output shaft. The stator and rotor eachincludes a plurality of bearing elements that may be fabricated frompolycrystalline diamond compacts (“PDCs”) that provide diamond bearingsurfaces that bear against each other during use.

In operation, high-pressure drilling fluid may be circulated through thedrill string and power section of the downhole drilling motor, usuallyprior to the rotary drill bit engaging the bottom of the borehole, togenerate torque and rotate the output shaft and the rotary drill bitattached to the output shaft. When the rotary drill bit engages thebottom of the borehole, a thrust load is generated, which is commonlyreferred to as “on-bottom thrust” that tends to compress and is carried,at least in part, by one of the thrust-bearing apparatuses. Fluid flowthrough the power section may cause what is commonly referred to as“off-bottom thrust,” which is carried, at least in part, by the otherthrust-bearing apparatus. The drilling fluid used to generate the torquefor rotating the rotary drill bit exits openings formed in the rotarydrill bit and returns to the surface, carrying cuttings of thesubterranean formation through an annular space between the drilledborehole and the subterranean drilling system. Typically, a portion ofthe drilling fluid is diverted by the downhole drilling motor to helpcool and lubricate the bearing elements of the thrust-bearingapparatuses. Insufficient heat removal may cause premature damage to thethrust-bearing apparatuses.

The on-bottom and off-bottom thrust carried by the thrust-bearingapparatuses can also be extremely large and generate significant amountsof energy. The operational lifetime of the thrust-bearing apparatusesoften can determine the useful life of the subterranean drilling system.Therefore, manufacturers and users of bearing apparatuses andsubterranean drilling systems continue to seek improved bearingassemblies and apparatuses with a longer useful life.

SUMMARY

Various embodiments of the invention relate to bearing assemblies,bearing apparatuses and motor assemblies that include superhard bearingelements having texture features configured to improve lubrication,cooling, and/or bearing capacity of the superhard bearing elements. Atleast some of the superhard bearing elements may be provided with atleast one texture feature formed in a lateral surface thereof to promotelubrication and/or cooling and enhance bearing capacity during use.

In an embodiment, a bearing assembly may include a plurality ofsuperhard bearing elements distributed circumferentially about an axis.Each of the superhard bearing elements may include a bearing surface. Atleast one of the plurality of superhard bearing elements may include atleast one texture feature formed in a lateral surface thereof. Thebearing assembly may also include a support ring that carries thesuperhard bearing elements. In an embodiment, the at least one texturefeature may be positioned and configured to direct lubricating fluidover and/or around the superhard bearing elements. In an embodiment, theat least one texture feature may be effective to increase a surface areaof the superhard bearing elements in contact with lubricating fluid. Inan embodiment, the at least one texture feature may follow a pathextending along a generally helical curve.

In an embodiment, a bearing apparatus may include two bearingassemblies. At least one of the two bearing assemblies may be configuredas any of the disclosed bearing assembly embodiments that are configuredto improve lubrication and/or cooling of the superhard bearing elementsduring use.

In an embodiment, a method for manufacturing a bearing assembly mayinclude forming at least one texture feature in a lateral surface of asuperhard bearing element. The method may further include securing thesuperhard bearing element to a support ring. In an embodiment, the atleast one texture feature may be formed before securing the superhardbearing element to the support ring. In an embodiment, the at least onetexture feature may be formed after securing the superhard bearingelement to the support ring. In an embodiment, forming the at least onetexture feature may include laser-cutting the texture feature in thelateral surface. In an embodiment, forming the at least one texturefeature may include computer numerical control milling the at least onetexture feature in the lateral surface.

Other embodiments include downhole motors for use in drilling systemsand subterranean drilling systems that may utilize any of the disclosedbearing apparatuses.

Features from any of the disclosed embodiments may be used incombination with one another, without limitation. In addition, otherfeatures and advantages of the present disclosure will become apparentto those of ordinary skill in the art through consideration of thefollowing detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate several embodiments, wherein identical referencenumerals refer to identical or similar elements or features in differentviews or embodiments shown in the drawings.

FIG. 1A is an isometric view of a thrust-bearing assembly according toan embodiment.

FIG. 1B is a top plan view of the thrust-bearing assembly shown in FIG.1A.

FIG. 1C is an isometric cutaway view taken along line 1C-1C of thethrust-bearing assembly shown in FIG. 1B.

FIG. 1D is an isometric view of one of the superhard bearing elementsremoved from the thrust-bearing assembly shown in FIG. 1A.

FIG. 1E is a side elevation view of the superhard bearing element shownin FIG. 1D.

FIG. 1F is a top plan view of the superhard bearing element shown inFIG. 1D.

FIG. 1G is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 2A is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 2B is a side elevation view of the superhard bearing element shownin FIG. 2A.

FIG. 2C is a top plan view of the superhard bearing element show in FIG.2A.

FIG. 3A is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 3B is a side elevation view of the superhard bearing element shownin FIG. 3A.

FIG. 3C is a top plan view of the superhard bearing element shown inFIG. 3A.

FIG. 4A is an isometric view of a thrust-bearing assembly according toan embodiment.

FIG. 4B is a top plan view of the thrust-bearing assembly shown in FIG.4A.

FIG. 4C is a cross-sectional view of the thrust bearing assembly shownin FIG. 4B taken along line 4C-4C.

FIG. 4D is an isometric view of one of the superhard bearing elementsremoved from the thrust-bearing assembly shown in FIG. 4A.

FIG. 4E is a side elevation view of the superhard bearing element shownin FIG. 4D.

FIG. 4F is a top plan view of the superhard bearing element shown inFIG. 4D.

FIG. 4G is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 4H is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 4I is an isometric view of a superhard bearing element according toanother embodiment.

FIG. 5A is an isometric view of a thrust-bearing apparatus that mayemploy any of the disclosed thrust-bearing assemblies according to anembodiment, with the housing shown in cross-section.

FIG. 5B is a cross-sectional view of the thrust-bearing apparatus shownin FIG. 5A taken along line 5B-5B.

FIG. 6A is an isometric view of a radial bearing assembly according toan embodiment.

FIG. 6B is an isometric cutaway view of the radial bearing assemblyshown in FIG. 6A.

FIG. 7 is an isometric cutaway view of a radial bearing apparatus thatmay utilize any of the disclosed radial bearing assemblies according tovarious embodiments.

FIG. 8 is a schematic isometric cutaway view of a subterranean drillingsystem that may utilize any of the disclosed bearing assembliesaccording to various embodiments.

DETAILED DESCRIPTION

Embodiments of the invention relate to bearing assemblies, bearingapparatuses and motors, pumps, or other mechanical assemblies thatinclude superhard bearing elements having texture features configured toimprove lubrication and/or cooling of the superhard bearing elements.During use, the superhard bearing elements may not be able toeffectively cool so at least some of the superhard bearing elements maybe provided with one or more texture features (e.g., at least onegroove, dimple, recess, groove pattern, or other topography) formedtherein to promote lubrication and/or cooling during use. FIGS. 1A and1B are isometric and top plan views of a thrust-bearing assembly 100according to an embodiment.

The thrust-bearing assembly 100 may form a stator or a rotor of athrust-bearing apparatus used in a subterranean drilling system. Asshown in FIGS. 1A and 1B, the thrust-bearing assembly 100 may include asupport ring 102 defining an opening 104 through which a shaft (notshown) of, for example, a downhole drilling motor may extend. Thesupport ring 102 may be made from a variety of different materials. Forexample, the support ring 102 may comprise a metal, alloy steel, a metalalloy, carbon steel, stainless steel, tungsten carbide, or any othersuitable metal or conductive or non-conductive material. The supportring 102 may include a plurality of recesses 106 (shown in FIG. 1C)formed therein.

The thrust-bearing assembly 100 further may include a plurality ofsuperhard bearing elements 108. In an embodiment, one or more of thesuperhard bearing elements 108 may have a generally cylindrical shapedbody. While the superhard bearing elements 108 are shown having agenerally cylindrical shaped body, the one or more of the superhardbearing elements may have a generally rounded rectangular shaped body, agenerally oval shaped body, a generally wedge shaped body, or any othersuitable shaped body. The superhard bearing elements 108 may include asuperhard table 110 bonded to a substrate 112, and a bearing surface 114of the superhard table 110. The superhard bearing elements 108 areillustrated in FIGS. 1A and 1B being distributed circumferentially abouta thrust axis 116 along which a thrust force may be generally directedduring use. As shown, gaps 118 may be located between adjacent ones ofthe superhard bearing elements 108. In an embodiment, at least one of,some of, or all of the gaps 118 may exhibit a width of about 0.00020inches to 0.100 inches, such as about 0.00040 inches to 0.0010 inches,or about 0.00040 inches to 0.080 inches. In other embodiments, the gaps118 may have widths that are relatively larger or smaller. In otherembodiments, the gaps 118 may substantially be zero.

Each of the superhard bearing elements 108 may be partially disposed ina corresponding one of the recesses 106 (shown in FIG. 1C which is anisometric cutaway view taken along line 1C-1C of the thrust-bearingassembly shown in FIG. 1B) of the support ring 102 and secured partiallytherein via brazing, press-fitting, threadly attaching, fastening with afastener, combinations of the foregoing, or another suitable technique.The superhard bearing elements 108 may be pre-machined to tolerances andmounted in the support ring 102 and/or mounted to the support ring 102and the bearing surfaces 114 thereof and planarized (e.g., by lappingand/or grinding) so that the bearing surfaces 114 are substantiallycoplanar. Optionally, one or more of the superhard bearing elements 108may exhibit a peripherally extending edge chamfer. However, in otherembodiments, the edge chamfer may be omitted.

FIGS. 1D-1G are isometric, side elevation, and top plan views of asuperhard bearing element 108 removed from the thrust-bearing assembly100. As used herein, a “superhard bearing element” is a bearing elementincluding a bearing surface that is made from a material exhibiting ahardness that is at least as hard as tungsten carbide.

In any of the embodiments disclosed herein, the superhard bearingelements 108 may each comprise one or more superhard materials, such aspolycrystalline diamond, polycrystalline cubic boron nitride, siliconcarbide, tungsten carbide, or any combination of the foregoing superhardmaterials. For example, the superhard table 110 may comprisepolycrystalline diamond and the substrate 112 may comprisecobalt-cemented tungsten carbide. Furthermore, in any of the embodimentsdisclosed herein, the polycrystalline diamond table may be leached to atleast partially remove or substantially completely remove ametal-solvent catalyst (e.g., cobalt, iron, nickel, or alloys thereof)that was used to initially sinter precursor diamond particles to formthe polycrystalline diamond. In another embodiment, an infiltrant usedto re-infiltrate a preformed leached polycrystalline diamond table maybe leached or otherwise removed to a selected depth from a bearingsurface. Moreover, in any of the embodiments disclosed herein, thepolycrystalline diamond may be un-leached and include a metal-solventcatalyst (e.g., cobalt, iron, nickel, or alloys thereof) that was usedto initially sinter the precursor diamond particles that form thepolycrystalline diamond and/or an infiltrant used to re-infiltrate apreformed leached polycrystalline diamond table. Examples of methods forfabricating the superhard bearing elements and superhard materialsand/or structures from which the superhard bearing elements can be madeare disclosed in U.S. Pat. Nos. 7,866,418; 7,998,573; and 8,034,136; andco-pending U.S. patent application Ser. No. 11/545,929; the disclosureof each of the foregoing patents and applications is incorporatedherein, in its entirety, by this reference.

The diamond particles that may be used to fabricate the superhard table110 in a high-pressure/high-temperature process (“HPHT)” may exhibit alarger size and at least one relatively smaller size. As used herein,the phrases “relatively larger” and “relatively smaller” refer toparticle sizes (by any suitable method) that differ by at least a factorof two (e.g., 30 μm and 15 μm). According to various embodiments, thediamond particles may include a portion exhibiting a relatively largersize (e.g., 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) and anotherportion exhibiting at least one relatively smaller size (e.g., 6 μm, 5μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than0.1 μm). In an embodiment, the diamond particles may include a portionexhibiting a relatively larger size between about 10 μm and about 40 μmand another portion exhibiting a relatively smaller size between about 1μm and 4 μm. In some embodiments, the diamond particles may comprisethree or more different sizes (e.g., one relatively larger size and twoor more relatively smaller sizes), without limitation. The resultingpolycrystalline diamond formed from HPHT sintering the aforementioneddiamond particles may also exhibit the same or similar diamond grainsize distributions and/or sizes as the aforementioned diamond particledistributions and particle sizes. Additionally, in any of theembodiments disclosed herein, the superhard bearing elements 108 may befree-standing (e.g., substrateless) and formed from a polycrystallinediamond body that is at least partially or fully leached to remove ametal-solvent catalyst initially used to sinter the polycrystallinediamond body.

Referring to FIG. 1D, at least some of the superhard bearing elements108 may include one or more texture features (e.g., at least one groove,dimple, recess, pattern, other topography, or combinations thereof)configured to influence cooling, lubrication, and/or bearing capacity ofthe superhard bearing elements 108 and/or the support ring 102. Forexample, one or more grooves 120 may be formed in a lateral surface 108Bof the superhard bearing elements 108. In an embodiment, the grooves 120may provide one or more flow paths for lubricating fluid between thelateral surfaces 108B of the superhard bearing elements 108 and/orsidewalls of the recesses 106 in the support ring 102. Such aconfiguration may increase the surface area of the superhard bearingelements 108 and/or the support ring 102 in contact with the lubricatingfluid to enhance cooling the thrust-bearing assembly 100. In anembodiment, the grooves 120 may direct lubricating fluid over and/oraround the superhard bearing elements 108 and/or the support ring 102 toenhance cooling and/or lubrication. In an embodiment, the grooves 120may influence flow characteristics of the lubricating fluid. In anembodiment, the grooves 120 may increase bearing capacity by helping toprevent the superhard bearing elements from overheating. For example,the grooves 120 may increase the surface area of the superhard bearingelements 108 to enhance heat transfer from the superhard bearingelements 108. In yet other embodiments, the grooves 120 may increasebearing capacity by providing engagement features for adhesives, epoxy,or other securing elements to help secure the superhard bearing elements108 in the recesses 106.

The one or more grooves 120 may be formed by electro-discharge machining(“EDM”), laser-cutting, computer numerical control (“CNC”) milling,grinding, combinations thereof, or otherwise machining the one or moregrooves 120 in the superhard bearing elements 108 before or aftersecuring the superhard bearing elements 108 to the support ring 102. Forexample, suitable laser-cutting techniques are disclosed in U.S.application Ser. No. 13/166,007 filed on Jun. 22, 2011, the disclosureof which is incorporated herein, in its entirety, by this reference.

As shown in FIG. 1E, some or all of the grooves 120 may follow agenerally straight path along the lateral surface 108B with a length Lthat extends axially generally between the bearing surface 114 and abottom surface 108A of the superhard bearing element 108. Such aconfiguration may develop eddies in the lubricating fluid flowinggenerally traverse to the grooves 120 to enhance the cooling of thelubricating fluid. In other embodiments, the length L of some or all ofthe grooves 120 may extend along only a portion of the lateral surface108B. For example, as shown in FIG. 1G, the grooves 120 may extendbetween the bearing surface 114 and a first location above the bottomsurface 108A of the superhard bearing element 108. In an embodiment, thefirst location may generally correspond to an upper surface of thesupport ring 102 such that the grooves 120 extend between the bearingsurface 114 and the upper surface of the support ring 102. Such aconfiguration may help to secure the superhard bearing elements 108within the recesses 106. For example, brazed-joint strength between thesuperhard bearing element 108 the recess 106 may be improved byproviding a lateral surface on the portion of the superhard bearingelement 108 within the recess 106 that generally corresponds to thelateral surface of the recess 106. Moreover, while the grooves 120 areillustrated following a generally straight path, some or all of thegrooves 120 may follow a generally arcuate path, a generallysemi-cylindrical path, a generally S-shaped path, a generally U-shapedpath, a generally V-shaped path, a generally linear path, or any othersuitable path.

In an embodiment, the length L of the grooves 120 may be about 0.3inches to about 1 inch, such as about 0.25 inches to about 0.5 inch orabout 0.10 inch to about 0.3 inch. However, in other embodiments, thelength L of the grooves 120 may be longer or shorter than the foregoingranges. As illustrated, each of the grooves 120 may have at leastsubstantially the same length L. However, in other embodiments, some orall of the grooves 120 may have substantially different lengths L,respectively. For example, in an embodiment, the superhard bearingelements 108 may include a first group of grooves 120 having lengths Lof about 0.25 inch and a second group of grooves 120 having lengths L ofabout 0.5 inches.

While all the superhard bearing elements 108 are shown includingsubstantially identical grooves 120, in other embodiments, only aportion of the superhard bearing elements 108 may have substantiallyidentical grooves 120, the superhard bearing elements 108 may havegrooves 120 of varying sizes and/or configurations, or only some of thesuperhard bearing elements 108 may include grooves 120.

The superhard bearing element 108 may have a height extending betweenthe bearing surface 114 and the bottom surface 108A. In an embodiment,the relationship between the length L of the grooves 120 and the heightof the superhard bearing elements 108 may be configured to influencecooling, lubrication and/or bearing capacity of the superhard bearingelements 108 and/or support ring 102. The length L of at least one ofthe grooves 120 may be at least: about five (5) percent; about fifteen(15) percent; about twenty five (25) percent; about fifty (50) percent;about seventy (70) percent; about eighty (80) percent; or about onehundred (100) percent of the height of the superhard bearing elements108. In other embodiments, the length L of one or more of the grooves120 may be about two (2) percent to about one hundred (100) percent;about ten (10) percent to about ninety (90) percent; or at least abouttwenty (20) percent of the height of at least one of the superhardbearing elements 108. In other embodiments, the length L of one or moreof the grooves 120 and the height of one or more of the superhardbearing elements 108 may be larger or smaller relative to each other.

As illustrated in FIG. 1F, each of the grooves 120 may be furtherdefined by a bottom portion 120B and opposing sidewalls 120A. In anembodiment, the grooves 120 may include edge features configured toinfluence flow conditions. For example, the grooves 120 may includebeveled edges, rounded edges, chamfered edges, or the like. One or moreof the grooves 120 may include edges that are sharpened, have notches,irregularly shaped, combinations thereof, or the like. Such aconfiguration may allow the grooves 120 to partially agitate, break-upor create desired flow characteristics in the lubricating fluid.

The grooves 120 may be substantially equidistantly and circumferentiallydistributed about a lateral periphery of the superhard bearing element108. In other embodiments, the grooves 120 may be unevenly distributedabout the periphery of the superhard bearing element 108. For example,the superhard bearing element 108 may include two grooves 120 on a firstside of the lateral surface 108B and no grooves on a second side of thelateral surface 108B generally opposite the first side. In anembodiment, one or more of the grooves 120 may be formed generallyparallel to an axis 122 of the superhard bearing element 108. In otherembodiments, one or more of the grooves 120 may be generallynon-parallel to the axis 122 of the superhard bearing element 108.

In an embodiment, the grooves 120 may have a generally V-shapedcross-section such that the bottom portion 120B is at least partiallydefined by the intersection of the opposing sidewalls 120A. In otherembodiments, the grooves 120 may have a generally rectangularcross-section, a generally U-shaped cross-section, a generallysemi-circular shaped cross-section, a generally parabolic shapedcross-section, a generally trapezoidal shaped cross-section,combinations thereof, or the like. The cross-section of the grooves 120may influence the flow conditions of the lubricating fluid and/or thecooling of the superhard bearing elements 108. For example, in anembodiment, at least one of the grooves 120 may have a portion includinga V-shaped cross-section configured to improve cooling of the superhardbearing element 108 and/or lubrication of the bearing surface 114 byincreasing the fluid velocity of the lubricating fluid through thatportion of the groove 120 and/or increasing the surface area in contactwith the lubricating fluid. In other embodiments, the grooves 120 mayinclude a first deeper cross-sectional shape followed by a secondshallower cross-sectional shape to pump or impel the lubricating fluid.

Referring still to FIG. 1F, at least one of the grooves 120 may have awidth W and a depth D. Variations of the depth D and/or the width W ofthe grooves 120 may help the grooves 120 lubricate and/or cool thesuperhard bearing elements 108. As shown in FIG. 1F, the depth D of thegrooves 120 extends between the bottom portion of the grooves 120 andthe lateral surface 108B. For example, the depth D may be about 0.1inches to about 0.4 inches, such as about 0.15 inches to about 0.25inches. As illustrated, the grooves 120 may have at least substantiallythe same depth D. However, in other embodiments, the grooves 120 mayhave at least substantially different depths D. In addition, the depthsD of a groove 120 may vary along its path. For example, at least one ofthe grooves 120 may have a depth D that includes a deeper portion and ashallower portion.

As shown in FIG. 1F, the width W of the grooves 120 extends between thegrooves 120. In an embodiment, the widths W of the grooves 120 may vary.For example, some or all of the grooves 120 may have a width W thattapers from the lateral surface 108B of the superhard bearing element108 toward the bottom portion of the grooves 120. Such a configurationmay provide the grooves 120 with a wider inlet for the lubricatingfluid. In an embodiment, the width W of the grooves 120 may be about 0.1inches to about 0.5 inches, such as about 0.2 inches to about 0.3inches. In other embodiments, the widths W of the grooves 120 may bewider or narrower. As illustrated, the grooves 120 may have at leastsubstantially the same width W. However, in other embodiments, some orall of the grooves 120 may have substantially different widths W.

In an embodiment, the relationship between the length L of one or moreof the grooves 120 and the depth D of one or more of the grooves 120 maybe configured to improve cooling, lubrication, and/or bearing capacityof the superhard bearing elements 108 and/or the support ring 102. Forexample, the length L of at least one of the grooves 120 may be atleast: about one hundred (100) percent; about two hundred (200) percent;about three hundred (300) percent; about four hundred (400) percent;about five hundred (500) percent; about six hundred (600) percent; aboutseven hundred (700) percent; or about eight hundred (800) percent of thedepth D of at least one of the grooves 120. In addition, the length L ofat least one of the grooves 120 may be: about four hundred (400) percentto eight hundred (800) percent; or about five hundred (500) percent toseven hundred (700) percent of the depth of the grooves 120; or aboutsix hundred (600) percent of the depth D of at least one of the grooves120. In other embodiments, the depth D of one or more of the grooves 120and the length L of one or more of the grooves 120 may be larger orsmaller relative to each other.

In an embodiment, the relationship between the length L of one or moreof the grooves 120 and the width W of one or more of the grooves 120 maybe configured to improve cooling, lubrication, and/or bearing capacityof the superhard bearing elements 108 and/or the support ring 102. Forexample, the length L of at least one of the grooves 120 may be atleast: about one hundred (100) percent; about two hundred (200) percent;about three hundred (300) percent; about four hundred (400) percent;about five hundred (500) percent; about six hundred (600) percent; aboutseven hundred (700) percent; or about eight hundred (800) percent of thewidth W of at least one of the grooves 120. In addition, the length L ofat least one of the grooves 120 may be: about four hundred (400) percentto about eight hundred (800) percent; or about five hundred (500)percent to about seven hundred (700) percent; or at least about sixhundred (600) percent of the width W of at least one of the grooves 120.In other embodiments, the width W of one or more of the grooves 120 andthe length L of one or more of the grooves 120 may be larger or smallerrelative to each other.

In an embodiment, the relationship between the depth D of one or more ofthe grooves 120 and the width W of the one or more of the grooves 120may be configured to improve cooling, lubrication, and/or bearingcapacity of the superhard bearing elements 108 and/or the support ring102. For example, the depth D of at least one of the grooves 120 may beat least: about fifty (50) percent; about one hundred (100) percent;about one hundred and fifty (150) percent; about two hundred (200)percent; or about three hundred (300) percent of the width W of at leastone of the grooves 120. In addition, the depth D of at least one of thegrooves 120 may be about fifty (50) percent to about one hundred andfifty (150) percent; or about one hundred (100) percent of the width Wof at least one of the grooves 120. In other configurations, the depth Dof one or more of the grooves 120 and the width W of one or more of thegrooves 120 may be larger or smaller relative to each other.

FIGS. 2A-2C are isometric, side elevation, and top plan views of asuperhard bearing element 208 according to an embodiment. The superhardbearing element 208 may include a superhard table 210 bonded to asubstrate 212, and a bearing surface 214 of the superhard table 210. Thesuperhard bearing element 208 may be made from any of the materialsdiscussed above for the superhard bearing elements 108. In theillustrated embodiment, the superhard bearing element 208 may have agenerally cylindrical shape. In other embodiments, however, thesuperhard bearing element 208 may have a generally rectangular shape, agenerally oval shape, a generally diamond shape, a generally triangularshape, a generally non-cylindrical shape, or other suitable shape.

The superhard bearing element 208 may include a plurality of grooves 220formed in a lateral surface 208B of the superhard bearing element 208.The superhard bearing element 208 may include two, four, seven, or anysuitable number of grooves 220. Some or all of the grooves 220 mayfollow a generally straight path along the lateral surface 208Bgenerally parallel to an axis 222 of the superhard bearing elements 208.While the grooves 220 are illustrated generally parallel to the axis 222of the superhard bearing elements 208, the one or more of the grooves220 may be formed generally nonparallel to the axis 222 of the superhardbearing elements 208. For example, the grooves 220 may follow agenerally curved path, a generally S-shaped path, a generally helicalpath, a generally V-shaped path, or the like. In an embodiment, some orall of the grooves 220 may have a length L that extends generallybetween the bearing surface 214 and a bottom surface 208A. In anotherembodiment, the length L of some or all of the grooves 220 may extendonly through a first location between the bearing surface 214 and thebottom surface 208A and a second location. In other embodiments, some orall of the grooves 220 may have a length L that extends through aportion of the bearing surface 214, through a portion of the substrate212, or a combination thereof.

As illustrated in FIG. 2C, the groove 220 may include a cross-sectionalarea at least partially defined between sidewalls 220A and a bottomportion 220B. In an embodiment, the cross-sectional shape may begenerally U-shaped. Such a configuration may increase surface areaand/or cause the lubricating fluid flowing across the grooves 220 toabruptly slow and change flow direction to enhance heat removal from thesuperhard bearing elements 208 to thereby reducing the risk of thesuperhard bearing elements 208 overheating. Moreover, flow of thelubricating fluid generally traverse to the grooves 220 may createeddies in the lubricating fluid to enhance the cooling effect of thelubricating fluid. In other embodiments, the grooves 220 may have agenerally v-shaped cross-section, a generally circular cross-section, agenerally rectangular cross-section, a generally rounded rectangularshape, a generally trapezoidal cross-section, combinations thereof, orthe like.

FIGS. 3A-3C are isometric, side elevation, and top plan views of asuperhard bearing element 308 according to an embodiment. The superhardbearing element 308 may include a superhard table 310 bonded to asubstrate 312, and a bearing surface 314 of the superhard table 310. Thesuperhard bearing element 308 may be made from any of the materialsdiscussed in relation to the superhard bearing elements 108. In theillustrated embodiment, the superhard bearing element 308 may have agenerally cylindrical shaped body. In other embodiments, however, thesuperhard bearing element 308 may have a generally rectangular shape, agenerally oval shape, a generally wedge shape, a generally triangularshape, or other suitable shape.

The superhard bearing element 308 may include a groove 320 formed in alateral surface 308B of the superhard bearing element 308. In otherembodiments, the superhard bearing element 308 may include two, three,or ten, or any suitable number of grooves 320.

The groove 320 may follow a path generally extending along aright-handed or left-handed curve or helix. The one or more grooves 320may follow a generally helical path, a generally double helical path, agenerally spiral path, or other suitable path. In an embodiment, thepath may correspond to a length of the one or more grooves 320. Thegroove 320 may extend about the periphery of the superhard bearingelement 308 between about two (2) and ten (10) times, or more. Such aconfiguration may allow the lubricating fluid to flow about thesuperhard bearing element 308 in a spiraling pattern to enhance heatremoval from the superhard bearing element 308. In other embodiments,the groove 320 may extend about the periphery of the superhard bearingelements 308 less than one (1) time, five (5) times, seven (7) times,ten (10) times, or any suitable number of times.

In an embodiment, the groove 320 may extend generally between thebearing surface 314 and the bottom surface 308A of the superhard bearingelement 308. In other embodiments, the groove 320 may extend generallybetween the bearing surface 314 and a first location between the bearingsurface 314 and a bottom surface 308A. In yet other embodiments, thegroove 320 may extend generally between the bottom surface 308A and asecond location between the bottom surface 308A and the bearing surface314. In other embodiments, the groove 320 may extend between a firstlocation and a second location.

FIGS. 4A and 4B are isometric and top plan views of a thrust-bearingassembly 400 according to an embodiment. The thrust-bearing assembly 400may form a stator or a rotor of thrust-bearing apparatus. As shown inFIGS. 4A and 4B, the thrust-bearing assembly 400 may include a supportring 402 defining an opening 404 through which a shaft (not shown) of,for example, a downhole drilling motor may extend. Similar to thesupport ring 102, the support ring 402 may be made from a variety ofdifferent materials. For example, the support ring 402 may comprise ametal, alloy steel, a metal alloy, carbon steel, stainless steel,tungsten carbide, or any other suitable conductive or non-conductivematerial. The support ring 402 may also include a plurality of recesses406 (shown in FIG. 4C) formed therein.

The thrust-bearing assembly 400 further may include a plurality ofsuperhard bearing elements 408. In an embodiment, one or more of thesuperhard bearing elements 408 may have a generally wedge shaped body.In other embodiments, one or more of the superhard bearing elements 408may have a generally rectangular body, a generally oval shaped body, orany other suitable shaped body. The superhard bearing elements 408 mayinclude a superhard table 410 bonded to a substrate 412, and a bearingsurface 414 of the superhard table 410. The superhard bearing elements408 are illustrated in FIGS. 4A and 4B being distributedcircumferentially about a thrust axis 416 along which a thrust force maybe generally directed during use. The superhard bearing elements 408 maybe circumferentially distributed about the thrust axis 416 in one row,two rows, three rows, or any number of suitable rows. As shown, gaps 418may be located between adjacent ones of the superhard bearing elements408 through which lubricating fluid may flow, as illustrated by flowarrows 421. In an embodiment, at least one of, some of, or all of thegaps 418 may exhibit a width of about 0.00020 inches to about 0.100inches, such as about 0.00040 inches to about 0.0010 inches, or about0.00040 inches to about 0.080 inches. In other embodiments, the gaps 418may have widths that are relatively larger or smaller. In otherembodiments, the gaps 418 may substantially be zero and the adjacentones of the superhard bearing elements 408 may abut each other. In otherembodiments, one or more of the gaps 418 may have different widths. Forexample, one pair of adjacent ones of the superhard bearing elements 408may be closer together than another pair of adjacent ones of thesuperhard bearing elements 408.

Each of the superhard bearing elements 408 may be partially disposed ina corresponding one of the recesses 406 (shown in FIG. 4C) of thesupport ring 402. The superhard bearing elements 408 may be partiallypositioned in and secured to the recesses 406 via brazing, welding,soldering, press-fitting, threadly attaching, fastening with a fastener,combinations of the foregoing, or another suitable technique. Similar tothe superhard bearing elements 108, the superhard bearing elements 408may be machined to tolerances and mounted in the support ring 402 and/orattached to the support ring 402. Bearing surfaces 414 may be planarized(e.g., by lapping and/or grinding) and/or positioned so that the bearingsurfaces 414 are substantially coplanar. Optionally, one or more of thesuperhard bearing elements 408 may exhibit a peripherally extending edgechamfer. However, in other embodiments, the edge chamfer may be omitted.

FIGS. 4D-4F are isometric, side elevation, and top plan views of asuperhard bearing element 408 removed from the thrust-bearing assembly400. The superhard bearing element 408 may be made from any of thematerials discussed above for the superhard bearing elements 108. Thesuperhard bearing elements 408 may include a first lateral surface 408A,a second lateral surface 408B, a first end surface 408C, and a secondend surface 408D. The first lateral surface 408A and the second lateralsurface 408B of each of the superhard bearing elements 408 may extendbetween the first end surface 408C and the second end surface 408D andvice versa. In an embodiment, the first lateral surface 408A and thesecond lateral surface 408B may be non-parallel to each other such thatthe superhard bearing elements 408 have a wedge-like shape. In theillustrated embodiment, both the first end surface 408C and the secondend surface 408D may have a convex curvature. In other embodiments, thefirst end surface 408C and the second end surface 408D may havesymmetrical edge configurations, asymmetrical edge configurations,curved edge configurations, irregular edge configurations, or othersuitable edge configurations. For example, the first end surface 408Cand the second end surface 408D may take the form of any portion of acircle, oval, square, rectangle, rhombus, triangle, or virtually anyother simple, complex, regular, irregular, or non-symmetrical geometricshape. Optionally, the first end surface 408C may have an area greaterthan an area of the second end surface 408D. In other embodiments, thefirst end surface 408C and the second end surface 408D may besubstantially the same size.

Like the superhard bearing elements 108, 208, and 308, one or more ofthe superhard bearing elements 408 may include one or more features(e.g., at least one groove) configured to influence bearing capacityand/or influence cooling of the superhard bearing elements 408. Forexample, one or more grooves 420 may be formed in the first lateralsurface 408A and/or the second lateral surface 408B of the superhardbearing elements 408. One or more of the grooves 420 may be formed byCNC milling, EDM, laser-cutting, grinding, combinations thereof, orotherwise machining the one or more grooves 420 in the superhard bearingelements 408 before or after securing the superhard bearing elements 408to the support ring 402.

In an embodiment, the grooves 420 may be formed substantially parallelto the bearing surface 414 of the superhard bearing element 408. Some orall of the grooves 420 may have a length that extends along a pathbetween the first end surface 408C and the second end surface 408D, orvice versa. In other embodiments, the length L of some or all of thegrooves 420 may extend along only a portion of the first lateral surface408A and/or the second lateral surface 408B. For example, the length Lof a groove 420 may extend between the first end surface 408C and anintermediate location between the first end surface 408C and the secondend surface 408D. Moreover, while the grooves 420 are illustratedfollowing a generally straight path, some or all of the grooves 420 mayfollow a generally curved path, a generally s-shaped path, a generallysinusoidal path, or any other suitable path. As illustrated, each of thegrooves 420 may have at least substantially the same length L. However,in other embodiments, some or all of the grooves 420 may havesubstantially different lengths L, respectively. Some or all of thegrooves 420 may be further defined by a bottom portion and opposingsidewalls. Similar to the grooves 120, at least one of the grooves 420may have a width W (not shown) and a depth D (not shown). Variations inthe D and/or the width W of the grooves 420 may help the grooves 420lubricate and/or cool the superhard bearing elements 408. While all thesuperhard bearing elements 408 are shown including substantiallyidentical grooves 420, in other embodiments, only a portion of thesuperhard bearing elements 408 may have substantially identical grooves420 and/or the superhard bearing elements 408 may have grooves 420 ofvarying sizes and/or configurations. The grooves 420 may include edgefeatures configured to influence flow conditions of the lubricatingfluid. For example, the grooves 420 may include beveled edges, roundededges, chamfered edges, or the like. One or more of the grooves mayinclude edges that are sharpened, notched, irregularly shaped,combinations thereof, or the like. Such a configuration may allow thegrooves 420 to partially agitate, break-up or create desired flowcharacteristics in the lubricating fluid.

The grooves 420 may be formed in rows positioned between the bearingsurface 414 and a first location above a bottom surface of the superhardbearing element 408. In an embodiment, the first location may generallycorrespond to an upper surface 402A of the support ring 402 such thatthe grooves 420 are positioned between the bearing surface 414 and theupper surface 402A of the support ring 402 during operation of thethrust-bearing assembly 400. In other embodiments, the first locationmay be below the upper surface 402A of the support ring 402. In yetother embodiments, the grooves 420 may be formed in rows positionedsubstantially between the bearing surface 414 and the bottom surface ofthe superhard bearing element 408 as shown in FIG. 4G. Such aconfiguration may allow the grooves 420 to be located within therecesses 406 during operation of the thrust-bearing assembly 400. Inother embodiments, the position of the rows of grooves 420 may vary fromone superhard bearing element 408 to another.

Referring again to FIG. 4C, the grooves 420 may influence flowconditions between adjacent ones of the superhard bearing elements 408during operation of the thrust-bearing assembly 400. For example, asshown by the flow arrow 421, the grooves 420 may increase the surfacearea of the superhard bearing elements 408 in contact with lubricatingfluid flowing between adjacent ones of the superhard bearing elements408. In an embodiment, the grooves 420 may direct lubricating fluidflowing between adjacent ones of the superhard bearing elements 408about and/or over the superhard bearing elements 408 and/or the supportring 402. For example, at least some of the grooves 420 may extend alonga curved path toward the bearing surface 414. In another embodiment, thegrooves 420 may increase the surface area of the superhard bearingelements 408 to enhance the heat transfer rate of the superhard bearingelement 408.

Embodiments of the invention further include other surface topographiesthat may be formed into a lateral surface of a superhard bearingelement. For example, dimpled, textured, recessed, cross-hatched, orother surface features or topography may be employed for increasing heattransfer from a superhard bearing element. In an embodiment, as shown inFIG. 4H, the lateral surface of the superhard bearing element 408 mayinclude a plurality of dimples 431 formed therein to help enhance heatremoval from the superhard bearing element 408. The dimples 431 maycover substantially the entire lateral surface, extending between thebearing surface 414 and a bottom surface of the superhard bearingelement 408 and the second end surface 408D and the first end surface(not shown). The dimples 431 may be generally concavely shaped, variablysized, or uniformly distributed. Flow of the lubricating fluid over thedimples 431 may create small vortices and/or increase the surface areaof the lateral surface in contact with the lubricating fluid to helpenhance heat removal from the superhard bearing element 408. While thedimples 431 are illustrated being generally concave, variably sized, andevenly distributed, in other embodiments, the dimples 431 may have othersuitable shapes, sizes, and/or distributions. For example, the dimples431 may be generally triangular shaped or cubic shaped and may bestaggered, similarly sized, and only on a portion of the lateralsurface.

In another embodiment, the lateral surface of the superhard bearingelement 408 may be cross-hatched to help enhance heat removal from thesuperhard bearing element 408. As shown in FIG. 4I, the cross-hatch 433may include a plurality of intersecting grooves extending between thebearing surface 414, the bottom surface, the second end surface 408D,and the first end surface (not shown) of the superhard bearing element408. The cross-hatch 433 may increase the surface area of the superhardbearing element 408 in contact with the lubricating fluid to help removeheat from the superhard bearing element 408. Moreover, the cross-hatch433 may direct lubricating fluid about and/or over the superhard bearingelement 408 to enhance heat removal.

Any of the above-described thrust-bearing assembly embodiments may beemployed in a thrust-bearing apparatus. FIG. 5A is an isometric view ofa thrust-bearing apparatus 500. The thrust-bearing apparatus 500 mayinclude a stator 540 configured as any of the previously describedembodiments of thrust-bearing assemblies. The stator 540 may include aplurality of circumferentially-adjacent superhard bearing elements 508.The superhard bearing elements 508 may include a bearing surface 514 andat least some of the superhard bearing elements 508 may exhibit, forexample, the configuration of the superhard bearing elements 108. Thesuperhard bearing elements 508 may be mounted or otherwise attached to asupport ring 502. The thrust-bearing apparatus 500 further may include arotor 550. The rotor 550 may include a support ring 552 and a pluralityof superhard bearing elements 558 mounted or otherwise attached to thesupport ring 552, with each of the superhard bearing elements 558 havinga bearing surface 554. As shown, a shaft 556 may be coupled to thesupport ring 552 and operably coupled to an apparatus capable ofrotating the shaft 556 in a direction R (or in a generally oppositedirection), such as a downhole motor. For example, the shaft 556 mayextend through and may be secured to the support ring 552 of the rotor550 by press-fitting or threadly coupling the shaft 556 to the supportring 552 or another suitable technique. A housing 560 may be secured tothe support ring 502 of the stator 540 and may extend circumferentiallyabout the shaft 556 and the rotor 550.

FIG. 5B is a cross-sectional view in which the shaft 556 and housing 560are not shown for clarity. In operation, lubricating filling fluid, ormud may be pumped between the shaft 556 and the housing 560, and betweenthe superhard bearing elements 558 of the rotor 550. Grooves 520 of thesuperhard bearing elements 558 of the rotor 550 may help directlubricating fluid over and/or around the superhard bearing elements 508and 558 which in turn can greatly reduce friction between the bearingsurfaces 514 of the stator 540 and the bearing surfaces 554 of the rotor550. The grooves 520 may also help cool the superhard bearing elements558 of the rotor 550 by increasing the surface area of the superhardbearing elements 558 in contact with the lubricating fluid thusimproving bearing capacity. In other embodiments, the grooves 520 helpcool the support ring 552 of the rotor 550 by increasing the surfacearea of the support ring 552 in contact with the lubricating fluid. Inaddition, the grooves 520 may help improve bearing capacity byincreasing heat removal from the thrust-bearing apparatus 500 toinfluence potential annealing. Moreover, under certain operationalconditions the thrust-bearing apparatus 500 may be operated as ahydrodynamic bearing. For example, where the rotational speed of therotor 550 is sufficiently great and the thrust load is sufficiently low,a fluid film may develop between the bearing surfaces 514 of the stator540 and the bearing surfaces 554 of the rotor 550. The fluid film mayhave sufficient pressure to reduce or prevent contact between therespective bearing surfaces 514, 554 and thus, substantially reduce wearof the superhard bearing elements 558 and/or the superhard bearingelements 508. In such a situation, the thrust-bearing apparatus 500 maybe described as operating hydrodynamically. Thus, the thrust-bearingapparatus 500 may be operated to improve lubrication, cooling, bearingcapacity, and/or as a hydrodynamic bearing.

The concepts used in the thrust-bearing assemblies and apparatusesdescribed above may also be employed in the radial bearing assembliesand apparatuses. FIGS. 6A and 6B are isometric and isometric cutawayviews, respectively, illustrating a radial bearing assembly 600according to an embodiment. The radial bearing assembly 600 may includea support ring 602 extending about a rotation axis 616. The support ring602 may include an inner peripheral surface 602C defining a centralopening 604 that is capable of receiving, for example, an inner supportring or inner race. The support ring 602 may also include an outerperipheral surface 602D. A plurality of superhard bearing elements 608may be distributed circumferentially about the rotation axis 616. Eachsuperhard bearing element 608 may include a superhard table 610including a concavely-curved bearing surface 614 (e.g., curved to lie onan imaginary cylindrical surface). Each superhard table 610 may bebonded or attached to a corresponding substrate 612 (shown in FIG. 6B).The superhard bearing elements 608 may have a generally cylindricalshape and each made from any of the materials discussed above for thesuperhard bearing elements 108. In other embodiments, the superhardbearing elements 608 may have a non-cylindrical shape, a generallywedge-like shape, a generally rectangular shape, a circular shape, orany other suitable shape. In an embodiment, at least some of thesuperhard bearing elements 608 may include a plurality of grooves 620formed in a lateral surface 608C of the superhard bearing element 608.The grooves 620 may be configured similar to the grooves 120, 220, 320,420, or any other groove disclosed herein. As illustrated in FIGS. 6Aand 6B, the superhard bearing elements 608 may be distributedcircumferentially about the rotation axis 616 in corresponding recesses606 formed in the support ring 602 and arranged in a single row. Inother embodiments, the superhard bearing elements 608 may becircumferentially distributed in two rows, three rows, four rows, or anynumber of rows.

FIG. 7 is an isometric cutaway view of a radial bearing apparatus 700according to an embodiment. The radial bearing apparatus 700 may includean inner race 782 (i.e., a rotor). The inner race 782 may define anopening 704 and may include a plurality of circumferentially-adjacentsuperhard bearing elements 786 distributed about a rotation axis 716,each of which includes a convexly-curved bearing surface 788. The radialbearing apparatus 700 may further include an outer race 790 (i.e., astator) that extends about and receives the inner race 782. The outerrace 790 may include a plurality of circumferentially-adjacent superhardbearing elements 708 distributed about the rotation axis 716, each ofwhich includes a concavely-curved bearing surface 714 curved tocorrespond to the convexly-curved bearing surfaces 788. The superhardbearing elements 708 and 786 may have a generally cylindrical shape andeach may be made from any of the materials discussed above for thesuperhard bearing elements 108. In other embodiments, the superhardbearing elements 708 and 786 may have a generally wedge-like shape, agenerally rectangular shape, a non-cylindrical shape, or any othersuitable shape. The terms “rotor” and “stator” refer to rotating andstationary components of the radial bearing apparatus 700, respectively.Thus, if the outer race 790 is configured to remain stationary, theouter race 790 may be referred to as the stator and the inner race 782may be referred to as the rotor.

At least some of the superhard bearing elements 786 and/or the superhardbearing elements 708 may include a plurality of grooves 720 formed in alateral surface thereof. One or more of the grooves 720 may beconfigured to influence lubrication, cooling, and/or bearing capacity ofthe superhard bearing elements 786, 708 and/or the inner race 782 and/orthe outer race 790. Moreover, under certain operating conditions thegrooves 720 may help form a fluid film similar to the description inrelation to FIGS. 5A and 5B. A shaft or spindle (not shown) may extendthrough the opening 704 and may be secured to the rotor 782 bypress-fitting the shaft or spindle to the rotor 782, threadly couplingthe shaft or spindle to the rotor 782, or another suitable technique. Ahousing (not shown) may also be secured to the stator 790 using similartechniques.

The radial bearing apparatus 700 may be employed in a variety ofmechanical applications. For example, so-called “rotary cone” rotarydrill bits, pumps, transmissions or turbines may benefit from a radialbearing apparatus discussed herein.

It is noted that the outer race 790 of the radial bearing apparatus 700is shown also including a plurality of circumferentially-distributedsuperhard bearing elements 708 with a plurality of grooves configured toinfluence lubrication, cooling, and/or bearing capacity of the radialbearing apparatus 700. However, in other embodiments, an outer race orthe inner race of a radial bearing apparatus may include a plurality ofcircumferentially distributed superhard bearing elements withoutgrooves.

Any of the embodiments for bearing apparatuses discussed above may beused in a subterranean drilling system. FIG. 8 is a schematic isometriccutaway view of a subterranean drilling system 800 according to anembodiment. The subterranean drilling system 800 may include a housing860 enclosing a downhole drilling motor 862 (i.e., a motor, turbine, orany other device capable of rotating an output shaft) that may beoperably connected to an output shaft 856. A thrust-bearing apparatus864 may be operably coupled to the downhole drilling motor 862. Thethrust-bearing apparatus 864 may be configured as any of the previouslydescribed thrust-bearing apparatus embodiments. A rotary drill bit 868may be configured to engage a subterranean formation and drill aborehole and may be connected to the output shaft 856. The rotary drillbit 868 is a fixed-cutter drill bit and is shown comprising a bit body890 having radially-extending and longitudinally-extending blades 892with a plurality of PDCs secured to the blades 892. However, otherembodiments may utilize different types of rotary drill bits, such ascore bits and/or roller-cone bits. As the borehole is drilled, pipesections may be connected to the subterranean drilling system 800 toform a drill string capable of progressively drilling the borehole to agreater size or depth within the earth.

The thrust-bearing apparatus 864 may include a stator 872 that does notrotate and a rotor 874 that may be attached to the output shaft 856 androtates with the output shaft 856. As discussed above, thethrust-bearing apparatus 864 may be configured as any of the embodimentsdisclosed herein. For example, the stator 872 may include a plurality ofcircumferentially-distributed superhard bearing elements 876 similar tothe superhard bearing elements 508 shown and described in thethrust-bearing apparatus 500 of FIG. 5A. The rotor 874 may include aplurality of circumferentially-distributed superhard bearing elements(not shown) such as shown and described in relation to FIGS. 1A-4G.

In operation, drilling fluid may be circulated through the downholedrilling motor 862 to generate torque and rotate the output shaft 856and the rotary drill bit 868 attached thereto so that a borehole may bedrilled. A portion of the drilling fluid may also be used to lubricateopposing bearing surfaces of the stator 872 and the rotor 874. When therotor 874 is rotated, grooves of the superhard bearing elements of therotor 874 may pump the drilling fluid onto the bearing surfaces of thestator 872 and/or the rotor 874, as previously discussed.

Although the bearing assemblies and apparatuses described above havebeen discussed in the context of subterranean drilling systems andapplications, in other embodiments, the bearing assemblies andapparatuses disclosed herein are not limited to such use and may be usedfor many different applications, if desired, without limitation. Thus,such bearing assemblies and apparatuses are not limited for use withsubterranean drilling systems and may be used with various mechanicalsystems, without limitation.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

What is claimed is:
 1. A method for manufacturing a bearing assembly,the method comprising: forming a superhard bearing element that includesa superhard table bonded to a substrate, the superhard table defining abearing surface and at least a portion of a lateral surface; forming atleast one texture feature in the lateral surface of the superhardbearing element, at least a portion of the at least one texture featureis formed in the superhard table; and securing the superhard bearingelement to a support ring.
 2. The method of claim 1, wherein the atleast one texture feature is formed in the lateral surface of the atleast one superhard bearing element before the at least one superhardbearing element is secured to the support ring.
 3. The method of claim1, wherein forming the at least one texture feature includes at leastone of laser-cutting or electro-discharge machining the at least onetexture feature in the lateral surface.
 4. The method of claim 1,wherein forming the at least one texture feature in the bearing surfaceincludes computer numerical control machining the at least one texturefeature in the lateral surface.
 5. The method of claim of claim 1,wherein the at least one texture feature is effective to increase asurface area of the at least one of the plurality of superhard bearingelements in contact with fluid during operation.
 6. The method of claim1, wherein the superhard table includes polycrystalline diamond.
 7. Themethod of claim 1, wherein the texture feature includes one or moregrooves.
 8. The method of claim 7, where the texture feature follows apath substantially extending between the bearing surface of the at leastone of superhard bearing elements and a bottom surface of the at leastone of the plurality of superhard bearing elements.
 9. The bearingassembly of claim 8, wherein the path includes at least one of agenerally curved path, a generally linear path, a generallysemi-cylindrical path, or a generally helical curved path.
 10. Themethod of claim 7, wherein the one or more groves include two or moreintersecting grooves.
 11. The bearing assembly of claim 1, wherein theat least one texture feature includes dimples, recesses, protrusions, orgrooves.
 12. A method for manufacturing a bearing apparatus, the methodcomprising: forming a first bearing assembly including: forming asuperhard bearing element that includes a superhard table bonded to asubstrate, the superhard table defining a bearing surface and at least aportion of a lateral surface; forming at least one texture feature inthe lateral surface of the superhard bearing element, at least a portionof the at least one texture feature is formed in the superhard table;and securing the superhard bearing element to a support ring; forming asecond bearing assembly including: securing to a plurality of secondbearing elements to a second support ring, each of the plurality ofsecond bearing elements including a second bearing surface; andpositioning the first bearing assembly and the second bearing assemblyrelative to each other such that the bearing surfaces of the firstbearing assembly generally oppose the second bearing surfaces of thesecond bearing assembly.
 13. The method of claim 12, wherein the atleast one texture feature is effective to increase a surface area of theat least one of the plurality of superhard bearing elements in contactwith fluid during operation.
 14. The method of claim 12, wherein thefirst bearing assembly is configured as a rotor, and the second bearingassembly is configured as a stator.
 15. The method of claim 12, whereinat least one of the second plurality of superhard bearing elementsincludes at least one texture feature.
 16. The method of claim 12,wherein positioning the first bearing assembly and the second bearingassembly relative to each other forms a thrust-bearing apparatus or aradial bearing apparatus.
 17. A method of operating a bearing apparatus,the method comprising: rotating a first bearing assembly and a secondbearing assembly relative to each other; and directing flow oflubrication fluid over and/or around one or more superhard bearingelements of the first bearing assembly by influencing flow oflubrication fluid with at least one texture feature formed in the one ormore superhard bearing elements, wherein the at least one texturefeature is effective to increase a surface area of the one or moresuperhard bearing elements in contact with the lubrication fluid. 18.The method of claim 17, wherein the at least one texture feature isformed in a lateral surface of the one or more superhard bearingelements.
 19. The method of claim 17, wherein the one or more superhardbearing elements include a superhard table bonded to a cemented carbidesubstrate, and the at least a portion of the at least one texturefeature is formed in the superhard table.
 20. The method of claim 17,wherein the texture feature includes one or more grooves, and at leastsome of the one or more grooves include edge features configured toinfluence the lubrication fluid.